Dictionary:Pole of spreading
Plate movement associated with sea-floor spreading can be described as rotation of one plate with respect to the other about an axis through the Earth’s center, the axis intersecting the Earth’s surface at the pole of spreading. Also called an Euler pole. Transform faults are latitude circles about the pole of spreading. Convergence is not necessarily normal to subduction. The rate of spreading is given as that at 90° even though the plates may not extend to 90°.